Over just the past few years, there has been an accelerated use of finely arrayed biological samples for gene expression, SNP analysis, drug discovery and other large-scale screening studies. Both membrane gridding and glass-slide microarraying methods have been used, with glass-slide microarraying techniques advancing most rapidly. Several techniques for generating arrays have been used, but perhaps the simplest and most widely utilized is pin-based arraying, wherein samples are extracted through capillary action from a microwell plate with an array of fine-point pins and "printed" onto glass slides in a very fine array. Currently available instruments are capable of producing arrayed slides with 10,000 to 20,000 samples at 100 to 200 micron spacing. Although new instrumentation and software for making and analyzing arrays have helped researchers make significant discoveries, the steps are still relatively lengthy, cumbersome, manually intensive and prone to error. The most ambitious portion of the proposed project is a rearraying instrument. This rearrayer will be able to randomly access individual samples from a library and assemble a subset into a new library. This is an important step in sub-selecting samples from a larger library prior to PCRing and arraying. The Phase II project will involve the design, construction and testing of fully functional prototype instruments. PROPOSED COMMERCIAL APPLICATION: This work will result in advanced-performance commercial rearraying robots. These will allow researchers to more rapidly make important discoveries using high-throughput screening assays. In addition, the proposed rearraying robot will be commercially useful for other applications in biology and chemistry laboratories outside of microarray analysis including DNA sequencing, drug discovery and combinatorial chemistry.